JP3288831B2 - Stencil printing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stencil printing machine for performing printing by winding a master perforated by a heating element such as a thermal head.

[0002]

2. Description of the Related Art A conventionally used master is a laminate obtained by laminating a thin thermoplastic resin film (about 2 to 8 μm thick) with a porous support made of Japanese paper, synthetic fibers, or a mixture of Japanese paper and synthetic fibers. It has a structure. The master film is heated and perforated by a heating element such as a thermal head, wound around a plate cylinder, supplied with ink from the inside of the plate cylinder, and pressed by a pressing member such as a press roller to form an opening in the plate cylinder and the master perforated. Printing is performed by exuding ink from the section and transferring it to printing paper. Since the ink passes through the fibers of the paper, such as Japanese paper, which is the porous support of the master, there are portions where the fibers are intertwined in a complicated manner (damaged portions), or the fibers traverse the perforated portions. In such a case, there is a problem that the permeation is hindered and a fibrous pattern appears on a solid portion, a thin line is cut or faded, that is, a so-called fibrous grain is generated.

[0003] Therefore, an attempt is made to reduce the problems caused by the fibrous grain by reducing the thickness of the porous support such as Japanese paper, which causes the generation of the fibrous grain, or by printing only with the thermoplastic resin film without using the porous support. Has been made. However, the apparent strength of the conventional master is borne by the porous support, and in the case of a thinner porous support or a master consisting of only a thermoplastic resin film, the strength of the master (lower ) Is greatly reduced.

A lock member for holding the leading end of the master is provided on the outer peripheral surface of the plate cylinder of the conventional stencil printing apparatus, and is composed of a stage portion parallel to the plate cylinder axis and a clamper member. Then, each time a new master is wound, the opening / closing member opens and closes the clamper member, and clamps the leading end of the master.

In general, a master is transported to a locking member by a platen roller or a feed roller provided downstream of the master in the direction of transport of the master. However, since the plate cylinder rotates, the master is prevented from colliding with a stage or a clamper member. Since the guide plate for guiding the master and the feed roller cannot be provided very close to the plate cylinder, there is no problem if the master has a stiffness like a master with a porous support. In a master having a thin body or a thermoplastic resin film alone, a slight waving phenomenon occurs due to shrinkage at the time of perforation, a habit of the film, or the like before reaching the locking member from the feed roller. If clamping is performed in this state, there is a problem that wrinkles are generated on the plate cylinder due to the undulation, resulting in poor printing. Therefore,
A substantially horizontal base paper support plate extending along the tangent plane of the top of the plate cylinder is provided near the plate cylinder, and the base paper support plate is formed of a rubber elastic body, and the edge on the master entry side has a center in the width direction. Attach an elastic member inclined in the direction of entry into the master from both sides toward the end, and sandwich the master between the elastic member and the holding plate to pull the master when mounting it on the plate cylinder and remove the wrinkles of the master. Is disclosed in Japanese Utility Model Publication No. 62-20297.

A base paper support plate provided near the plate cylinder and extending substantially horizontally along a tangent plane of the top of the plate cylinder, and a base paper holding member made of an elastic body disposed above the base paper support plate In the vicinity of both side edges of the base paper support plate, it is rotatably supported at a position below the tangent plane of the plate cylinder top, so that the top of the outer peripheral surface faces the base paper support plate, and its central axis is It is composed of at least two rollers disposed so as to be inclined in the master transport direction as going from the side edge of the plate cylinder to the center.The master is sandwiched between the base paper support plate and the base paper holding member, A base paper guide device that removes wrinkles of a master by giving a bias to the master
No. 866 discloses this.

[0007]

However, with the techniques disclosed in the above publications, it is difficult to uniformly apply tension to the master, and in particular, a master made of only a low-strength thermoplastic resin film. In this case, even if the master wraps around the plate cylinder due to the viscosity of the ink, even if the master wraps around the plate cylinder even if the master is pressed by an elastic member, the master may be loosened due to the unevenness of the tension. There is a problem that it sticks to the top and does not move, but is crushed and wrinkled.

[0008] It is an object of the present invention to provide a stencil printing machine in which wrinkles on the master are prevented from occurring when the master is wound around the plate cylinder, even if a master made of only a thermoplastic resin film is used.

[0009]

According to the first aspect of the present invention,
A stencil printing machine comprising a plate cylinder of a porous cylinder and plate making means for making a master in accordance with image information, wherein the plate is provided in the vicinity of the plate cylinder so as to be able to freely contact with and separate from the plate cylinder. A spreading roller for contacting the master over the entire width of the master wound around the cylinder and applying tension to the master on the plate cylinder and locking the master on the outer peripheral surface of the plate cylinder; It is characterized by having a raised portion at the peripheral edge excluding the part and at both ends of the peripheral edge.

According to a second aspect of the present invention, in the stencil printing machine according to the first aspect, the contact surface of the raised portion with the master further increases frictional force between the raised portion and the master. A member is provided.

According to a third aspect of the present invention, in the stencil printing machine according to the first aspect, a suction / adhesion layer having an adsorbing property and / or an adhesive property is further provided on a contact surface of the raised portion with the master. It is characterized by being provided.

[0012]

[0013]

According to the first aspect of the present invention, the spreading roller, which is provided to be able to freely contact and separate from the plate cylinder, comes into contact with the master wound around the plate cylinder over the entire width thereof. A protruding portion formed on the periphery except for a portion for locking the master comes into contact with the master.

According to the second aspect of the present invention, the friction member provided on the master contact surface of the raised portion increases the frictional force between the master contact surface of the raised portion and the master.

According to the third aspect of the present invention, the suction / adhesion layer provided on the master contact surface of the raised portion adsorbs and / or adheres the master.

[0016]

[0017]

FIG. 1 shows an embodiment of the present invention. In FIG. 1, a plate cylinder 2 supported by a spindle 1 also serving as an ink supply pipe and rotationally driven by a driving means (not shown) having a torque limiter has a spindle. A stage 3 is provided on the outer peripheral surface of the stage 3 and is disposed in parallel with the stage 1 and receives the leading end of the master. A clamper 4 for holding the tip of the master with the stage 3
Is pivotally mounted on the outer peripheral surface of the plate cylinder 2 by a shaft 4a, and is rotatable by transmitting a driving force by an opening / closing member (not shown).

A mesh-shaped opening 2a is formed on the outer peripheral surface of the plate cylinder 2, and the opening 2a is formed at the periphery of both ends of the stage portion 3 which is a portion for locking the master and the periphery of the plate cylinder 2. Except for the portion, it is formed over the entire outer peripheral surface of the plate cylinder 2. Further, as shown in FIG. 2, a raised portion 2b is formed only at the peripheral edge of the stage portion 3 excluding the peripheral portions at both ends and at both ends of the peripheral portion, that is, around the opening 2a. The amount of protrusion from the opening 2a is set to 0.1 to 0.3 mm. A friction member 2c is provided on the contact surface of the raised portion 2b with the master.
Examples of the friction member 2c include sandpaper of about No. 300 to No. 400. The raised portions 2b may be formed around both ends of the stage portion 3 or over the entire outer peripheral surface of the plate cylinder 2 excluding the stage portion 3. A well-known ink supply unit (not shown) is provided inside the plate cylinder 1, and ink is supplied to the ink supply unit through the spindle 1 by an external ink supply device.

On the right side of the plate cylinder 1, a master roll 5 substantially made of a thermoplastic resin film is rotatably supported by a support shaft 6. In the vicinity of the master roll 5, a plurality of heating elements are provided, and a thermal head 7 for performing perforation and plate making on the master 5a pulled out from the master roll 5 is rotated counterclockwise by a stepping motor (not shown). A plate making means 9 including a platen roller 8 for conveying the master 5a while pressing it against the thermal head 7 is provided. On the downstream side of the plate making means 9 in the master transport direction, a transport roller pair 10 for transporting the master 5a toward the stage 3 is provided. This transport roller pair 1
Numeral 0 is rotationally driven by driving means (not shown), and its peripheral speed is set slightly higher than the peripheral speed of the platen roller 8. A well-known guillotine-type cutting means 11 composed of an upper blade 11a and a lower blade 11b, which cuts the master 5a, is disposed downstream of the conveying roller pair 10 in the master conveying direction. On the downstream side of the cutting means 11 in the master transport direction,
A guide plate 12 for guiding the master 5a to the stage 3 is provided. The guide plate 12 is desirably disposed as close as possible to the stage unit 3 because the conveyed master 5a is very thin and has no rigidity. In order to avoid interference with the clamper 4, it is arranged rotatably between a solid line position and a two-dot chain line position in the figure. As shown in FIG. 7, the guide plate 12 is rotatably supported by a support shaft 12a.
2b and 12c protrude. An elongated hole 26a formed near one end of a guide plate arm 26 made of a plate material is engaged with the protrusion 12b protruding toward the near side. At the other end of the guide plate arm 26, a plunger 27a of a solenoid 27 attached to the main body of the stencil printing apparatus is rotatably mounted on a shaft 28. One end of a tension coil spring 29 is attached to the protrusion 12c protruding to the back side, and the other end of the tension coil spring 29 is attached to the stencil printing apparatus main body. With this configuration, the guide plate 12
Is rotated by a solenoid 27 and a tension coil spring 29.

Above the plate cylinder 2, it is swingably provided,
A spreading roller 13 for applying tension to the master 5a wound on the outer peripheral surface of the plate cylinder 2 and an eccentric cam 19 for swinging the spreading roller 13 are provided. The spreading roller 13 includes a roller 14, a drive arm 15, an arm 16,
It is mainly composed of a central shaft 17, rollers 18, and the like. The roller 14 is formed to have a width larger than the width of the master 5a, and is rotatably supported between the drive arm 15 and the arm 16 by a shaft 14a. The roller 14 is desirably smooth and has a small frictional force so that the master 5a can easily move when the master 5a contacts the roller 14. Specifically, an elastic body such as rubber coated with Teflon may be used.

A shaft 14a is rotatably attached to one end of the drive arm 15, and a support shaft 18a for supporting the roller 18 is fixed to the other end. The roller 18 is rotatably supported by a support shaft 18a. A central shaft 17 is fixed to a substantially central position of the drive arm 15.
A shaft 14a is rotatably attached to one end of the arm 16, and a center shaft 17 is fixed to the other end.
The central shaft 17 supports the drive arm 15 and the arm 16,
It is rotatably attached to a side plate (not shown) of the stencil printing apparatus main body.

The eccentric cam 1 is located above the spreading roller 13.
9 are provided. The eccentric cam 19 is fixed to a rotatable eccentric shaft 19a, and the eccentric shaft 19a is rotated by a stepping motor (not shown). The outer peripheral surface of the eccentric cam 19 is always in contact with the outer peripheral surface of the roller 18. The rotation of the eccentric cam 19 causes the spreading roller 13 to swing about the central axis 17, and the outer peripheral surface of the roller 14 2 is configured to be in contact with or separated from the master 5a wound on the outer peripheral surface of the master 2.

Hereinafter, the operation of this embodiment having the above configuration will be described. When a document is set on a document reading unit (not shown) and a plate making start signal is output, a plate discharging device (not shown) operates, and the used master of the previous plate wound around the outer peripheral surface of the plate cylinder 2 is peeled and discarded. . Thereafter, the plate cylinder 2 is driven to rotate by driving means (not shown), and stops at a plate feeding position where the clamper 4 is located almost directly above as shown in FIG. It will be in the plate standby state. When the plate cylinder 2 stops, the guide plate 12 is also rotated counterclockwise by energizing the solenoid 27, and is positioned from the initial position indicated by the two-dot chain line in FIG. 1 to the plate feeding position indicated by the solid line.

When the plate cylinder 2 and the guide plate 12 are positioned at the plate feeding position and are in the plate feeding standby state, the platen roller 8
And the conveying roller pair 10 is rotationally driven by each driving means,
The master 5a is transported. The master 5a is pressed against the thermal head 7 by the platen roller 8 and is subjected to heat perforation in accordance with the image information of the document. At this time, the peripheral speed of the transport roller pair 10 is slightly lower than the peripheral speed of the platen roller 8. Since the setting is fast, the master 5a that has been made
Is given an appropriate tension.

When the master 5a is conveyed and the number of steps of a stepping motor (not shown) for driving the platen roller 8 determines that the tip of the master 5a has reached the clamper 4, an opening / closing member (not shown) moves the clamper 4 to the position. The master 5 a is rotated in the clockwise direction, and the tip of the master 5 a is held between the master 5 a and the stage 3. At the same time when the clamper 4 is closed, the plate cylinder 2 also starts to rotate in the counterclockwise direction, and the winding is started. At the time of winding, the plate cylinder 2 is configured to wind while applying a constant tension to the master by the function of a torque limiter provided in its driving means.

When the plate cylinder 2 rotates to a position where the roller 14 and the end of the raised portion 2b correspond to each other, a stepping motor (not shown) for driving the eccentric shaft 19a operates to rotate the eccentric cam 19 by 180 degrees. When the eccentric cam 19 rotates, the spreading roller 13 rotates clockwise about the central axis 17, and as shown in FIG.
Abuts on the raised portion 2b via a. The master 5a is applied with tension from the roller 14 in addition to the tension from the plate cylinder 2, and is supported on a friction member 2c provided on the surface of the raised portion 2b, and is wound around the outer peripheral surface of the plate cylinder 2. . This state is shown in FIG.
Shown in

When it is determined that the plate making is completed by the step number of the stepping motor (not shown) for driving the platen roller 8 reaching the set number, the platen roller 8 and the transport roller pair 10 are stopped, and the cutting means 11 is stopped. Operates to disconnect the master 5a. The cut master 5a is pulled out by the rotation of the plate cylinder 2, and is wound around the outer peripheral surface of the plate cylinder 2. When the rear end of the master 5a passes through the roller 14, a stepping motor (not shown) that drives the eccentric shaft 19a operates to rotate the eccentric cam 19 by 180 degrees to return the spreading roller 13 to the initial position shown in FIG. At the same time, the power supply to the solenoid 27 is cut off to return the guide plate 12 to the initial position shown by the two-dot chain line in FIG. 1, and the plate feeding operation is completed. After the completion of plate feeding, a printing operation is performed.

In the above embodiment, when the spreading roller 13 rotates about the central shaft 17 by the rotation of the eccentric cam 19, the spreading roller 13 is configured to rotate by its own weight. 3, one end of a tension spring 20 is attached to a position between the fixed position of the center shaft 17 of the drive arm 15 and the fixed position of the support shaft 18a, and the other end of the tension spring 20 is stencil-printed. It may be configured to be fixed to the side plate of the apparatus, and the spreading roller 13 may be rotated by the urging force of the tension spring 20.

Further, instead of the friction member 2c, an absorbing / adhering layer having an adsorbing property and / or an adhesive property may be used. Those having a plurality of micro suction cups can be mentioned as those having absorptivity, and those having a thin silicon rubber layer or a rubber paste layer can be mentioned as those having an adhesive property. The absorption / adhesion required for the absorption / adhesion layer may be about 5 g / cm 2.

FIG. 6 shows another embodiment of the present invention. This embodiment is different from the first embodiment in that the stage 3, the clamper 4, the transport roller pair 10, the guide plate 12, and the eccentric cam 19 are deleted, and the heater wire 21 is replaced with the spreading roller 13 instead of the cutting means 11 and the spreading roller 13. Wearing roller 22
This is different from the above embodiment in having

One end 2 of the raised portion 2b on the outer peripheral surface of the plate cylinder 2
The surface of e has an adhesive and / or adsorptive
An adhesive layer is formed. Below the platen roller 8, a heater wire 21 movably provided in the horizontal direction is provided. A spreading roller 22 is provided below the heater wire 21. The spreading roller 22 is a shaft 1
It mainly comprises a roller 14 fixed to 4a, arms 23 and 24 for rotatably supporting the roller 14, and a central shaft 25 for supporting each arm. Center axis 2
5 is rotatably supported on a side plate of the stencil printing apparatus, and a gear (not shown) is fixed to one end thereof,
It is rotated by driving means (not shown). Thereby, the roller 14 is selectively rotated between a solid line position and a two-dot chain line position in FIG.

When the plate making signal is output, after the plate discharging operation is completed, the plate cylinder 2 is driven to rotate by driving means (not shown),
And stops at the plate feeding position shown in FIG. Plate cylinder 2
Is positioned at the plate feeding position and enters the plate feeding standby state, the platen roller 8 is rotationally driven by a driving unit (not shown), and the master 5a is conveyed. The master 5a is pressed against the thermal head 7 by the platen roller 8, and is subjected to heat perforation in accordance with the image information of the document.

As the conveyance of the master 5a proceeds, it is determined from the number of steps of a stepping motor (not shown) that drives the platen roller 8 that the leading end of the master 5a has reached a predetermined locking position on the outer peripheral surface of the plate cylinder 2. Then, the driving means (not shown) rotates the center shaft 25 in the counterclockwise direction to position the roller 14 at the position indicated by the two-dot chain line in the figure, and locks the leading end of the master 5a on the surface of the one end 2e. . At the same time as the master 5a is locked on the outer peripheral surface, the plate cylinder 2 also starts to rotate clockwise, and winding is started. At the time of winding, a constant tension is applied to the master 5a by the function of the torque limiter provided in the driving means of the plate cylinder 2, and further tension is applied by being pressed by the raised portion 2b by the roller 14. Is done.

When it is determined that the plate making is completed by the number of steps of a stepping motor (not shown) for driving the platen roller 8 reaching the set number, the platen roller 8 stops and the heater wire 21 moves, and the master line is moved. 5a is cut. The cut master 5a is pulled out by the rotation of the plate cylinder 2, and is wound around the outer peripheral surface of the plate cylinder 2. When the rear end of the master 5a passes through the roller 14, the driving means (not shown) rotates the central shaft 25 clockwise to return the roller 14 to the position shown by the solid line in the figure, and the plate feeding operation is completed.

With such a configuration, the clamper 4, the transport roller pair 10, the guide plate 12, and the like can be omitted, so that the size of the apparatus and the cost of the apparatus can be reduced.

In the above embodiment, if the surface of the heater wire 21 for fusing the master 5a is coated with a fluorine resin or the like, the melted master adheres to the heater wire 21 at the time of fusing and the cutting of the master is unstable. And the problem that the cut surface becomes uneven and the conveyance and the engagement with the outer peripheral surface of the plate cylinder become unstable.

The master substantially composed of only a thermoplastic resin film used in each of the above-mentioned embodiments means that the master is composed of only a thermoplastic resin film, and that the thermoplastic resin film has a trace component such as an antistatic agent. , And one or more thin films such as an overcoat layer formed on both main surfaces of the thermoplastic resin film, that is, at least one of the front and back surfaces.

[0038]

According to the first aspect of the present invention, the spreading roller, which is provided so as to be able to freely contact and separate from the plate cylinder, comes into contact with the master wound around the plate cylinder over the entire width thereof, and also on the outer peripheral surface of the plate cylinder. The ridge formed on the periphery except the part that locks the master contacts the master, so the tension is reliably applied to the master, and the occurrence of wrinkles on the master during winding is more reliably prevented can do.

According to the second aspect of the present invention, the friction member provided on the master contact surface of the raised portion increases the frictional force between the master contact surface of the raised portion and the master. , The occurrence of wrinkles on the master during winding can be prevented.

According to the third aspect of the present invention, since the suction / adhesion layer provided on the master contact surface of the raised portion adsorbs and / or adheres the master, the displacement of the master on the outer peripheral surface of the plate cylinder is more reliable. , And the occurrence of wrinkles on the master during winding can be more reliably prevented.

[0041]

[Brief description of the drawings]

FIG. 1 is a schematic side view of a main part of a stencil printing apparatus employing an embodiment of the present invention.

FIG. 2 is a developed plan view of a plate cylinder for explaining an embodiment of the present invention.

FIG. 3 is a perspective view of a spreading roller illustrating an embodiment of the present invention.

FIG. 4 is a schematic side view of a main part of a stencil printing machine for explaining an embodiment of the present invention.

FIG. 5 illustrates a plate cylinder, a roller, and an embodiment of the present invention.
It is a figure showing the state of a master.

FIG. 6 is a schematic side view of a main part of a stencil printing apparatus employing another embodiment of the present invention.

FIG. 7 is a partial side view illustrating a guide plate rotating means according to an embodiment of the present invention.

[Explanation of symbols]

 2 plate cylinder 2b raised portion 2c friction member 5a master 9 plate making means 13,22 spreading roller

Claims (3)

(57) [Claims] 1. A stencil printing machine having a plate cylinder of a porous cylindrical body and plate making means for making a master according to image information, wherein said plate printing device is provided near said plate cylinder so as to be freely movable toward and away from said plate cylinder. And a spreading roller that contacts the master over the entire width of the master wound around the plate cylinder and applies tension to the master on the plate cylinder, and includes a spreading roller on the outer peripheral surface of the plate cylinder. A stencil printing machine having a peripheral portion excluding a portion for locking a master and a raised portion at both ends of the peripheral portion. 2. A contact surface of the raised portion with the master,
2. The stencil printing apparatus according to claim 1, further comprising a friction member for increasing a frictional force between the raised portion and the master. 3. A contact surface of the raised portion with the master,
2. The stencil printing apparatus according to claim 1, further comprising a suction / adhesion layer having an adsorption property and / or an adhesive property.